Intake airways9

The manager shall ensure that, apart from those persons who are going to or leaving their place of work at the beginning or end of a shift, not more than 50 persons are employed below ground in any part of the mine unless—

a

there are two separate intake airways into that part of the mine which are connected only in such a way that in the event of a fire, transmission of the products of combustion from one airway to the other is prevented so far as is reasonably practicable; or

b

there is one intake airway which is constructed of suitable fire resistant materials and is free, so far as is reasonably practicable, from the risk of fire.